摘要
模拟三峡库区消落带土壤水分变化特征设置常规生长水分条件(CK组,土壤含水量为田间持水量的60%～63%)、轻度干旱水分胁迫(T1组,土壤含水量为田间持水量的47%～50%)、土壤水饱和(T2组,土壤表面一直处于潮湿状态)以及水淹(T3组,苗木根部淹水超过土壤表面1 cm)4个不同处理组,对落羽杉和池杉当年实生幼苗的光合特性以及生理生态适应机制进行对比研究.研究发现在T2和T3组,落羽杉幼苗的光合色素含量显著低于池杉幼苗.在CK组,2树种幼苗净光合速率Pn、蒸腾速率Tr、气孔导度Gs、水分利用效率WUE、表观光能利用效率LUEapp和表观CO2利用效率CUEapp的平均值均无显著差异.但是在T2组,落羽杉幼苗的Pn、LUEapp和CUEapp平均值显著低于池杉幼苗的平均值,与之在T3组的Gs平均值显著大于池杉幼苗形成鲜明对比.在T1组,2种植物的Pn、LUEapp和CUEapp平均值显著低于其他3种水分条件下的值.池杉幼苗在T1组仍然保持着与CK组一致的Tr和Gs平均值,与落羽杉幼苗在T1组的Tr和Gs平均值显著低于CK组形成对比.研究结果表明,落羽杉和池杉均具有耐水湿性特点,均可考虑列为三峡库区消落带防护林体系建设树种.但池杉树种的耐旱与耐水湿特性优于落羽杉,最适宜于在土壤饱和水环境中生长.
Four different kinds of water treatment were applied to compare the photosynthetic characteristics of Taxodium distichum and T. ascendens seedlings under simulation of soil water change of the hydro-fluctuation belt in the Three Gorges Reservoir Area. The aim was to shed light on the plants＇ physio-ecological adaptation to changing water levels for tree species selection and revegetation purposes. The water treatments were normal growth water condition （ i.e. CK with soil water content being 60 % - 63 % of soil water field capacity）, light drought water stress condition （i.e. T1 with soil water content being 47 % - 50% of soil water field capacity）, soil water saturation condition （i. e. T2 with soil water content being saturated） and soil submersion condition （i.e. T3 with soil being submerged 1 cm）. The results showed that the photosynthetic pigment content of T. distichum was significantly lower than that of T. ascendens both in T2 and T3 . In CK, the seedlings of T. distichum did not differ from the seedlings of T. ascenderts in net photosynthetic rate （ Pn）, transpiration rate （ Tr）, stomatal conductance （ Gs）, water use efficiency （ WUE）, apparent light use efficiency （LUEapp） or apparent CO2 use efficiency （CUEapp） . However, the seedlings of T. distichum had significantly lower Pn, lower LUEapp and lower CUEapp in T2 as well as significantly higher Gs in T3 than those of the T. ascendens seedlings in the same treatment. In T1 , the seedlings of both T. distichum and T. ascendens had significantly lower Pn, lower LUEapp and lower CUEapp than those of their respective other three treatments. The Tr and Gs of T. ascendens seedlings in T1 did not differ from those of its CK, whereas the Tr and G, of T. distichum seedlings in T1 were significantly lower than those of its CK. The results verified that beth T. distichum and T. ascendens took on features of watertolerant and hydrophilic plants, which can be considered as two species to be chosen for the building of protection forest system of the hydro-fluctuation belt in the Three Gorges Reservoir Area. When compared with T. distichum seedlings, the T. ascendens seedlings have better capacity to tolerate water and drought stress, and can grow very well under soil water saturation.
出处
《林业科学》
EI
CAS
CSCD
北大核心
2005年第6期28-34,共7页
Scientia Silvae Sinicae
基金
国家自然科学基金资助项目(30370279)
重庆市发改委2003年重大项目([2003]1136)。
关键词
三峡库区
消落带
土壤水分
落羽杉幼苗
池杉幼苗
光合作用
Three Gorges Reservoir Area
hydro-fluctuation belt
soil water change
Taxodium distichum seedlings
Taxodium ascendens seedlings
photosynthesis
作者简介
钟章成为通讯作者。
